WireGuard for the NT Kernel

High performance in-kernel WireGuard implementation for Windows

WireGuardNT is an implementation of WireGuard, for the NT Kernel as used in Windows 7, 8, 8.1, 10, and 11, supporting AMD64, x86, and ARM64 processors.

Not the droids you're looking for

If you've come here looking to run WireGuard on Windows, you're in the wrong place. Instead, head on over to the WireGuard Download Page to download the WireGuard application. Alternatively, if you've come here looking to embed WireGuard into your Windows program, you are still in the wrong place. Instead, head on over to the embeddable DLL service project, to get everything you need to bake WireGuard into your Windows programs. These projects use WireGuardNT inside.

Usage

Download

WireGuardNT is deployed as a platform-specific wireguard.dll file. Install the wireguard.dll file side-by-side with your application. Download the dll from the wireguard-nt download server, alongside the header file for your application described below.

API

Include the wireguard.h file in your project simply by copying it there and dynamically load the wireguard.dll using LoadLibraryEx() and GetProcAddress() to resolve each function, using the typedefs provided in the header file. The InitializeWireGuardNT function in the example.c code provides this in a function that you can simply copy and paste.

With the library setup, WireGuardNT can then be used by first creating an adapter, configuring it, and then setting its status to "up". Adapters have names (e.g. "OfficeNet") and types (e.g. "WireGuard").

WIREGUARD_ADAPTER_HANDLE Adapter1 = WireGuardCreateAdapter(L"OfficeNet", L"WireGuard", &SomeFixedGUID1);
WIREGUARD_ADAPTER_HANDLE Adapter2 = WireGuardCreateAdapter(L"HomeNet", L"WireGuard", &SomeFixedGUID2);
WIREGUARD_ADAPTER_HANDLE Adapter3 = WireGuardCreateAdapter(L"Data Center", L"WireGuard", &SomeFixedGUID3);

After creating an adapter, we can use it by setting a configuration and setting its status to "up":

struct
{
    WIREGUARD_INTERFACE Interface;
    WIREGUARD_PEER FirstPeer;
    WIREGUARD_ALLOWED_IP FirstPeerAllowedIP1;
    WIREGUARD_ALLOWED_IP FirstPeerAllowedIP2;
    WIREGUARD_PEER SecondPeer;
    WIREGUARD_ALLOWED_IP SecondtPeerAllowedIP1;
} Config = {
    .Interface = {
        .Flags = WIREGUARD_INTERFACE_HAS_PRIVATE_KEY,
        .PrivateKey = ...,
        .PeersCount = 2
    },
    .FirstPeer = {
        .Flags = WIREGUARD_PEER_HAS_PUBLIC_KEY | WIREGUARD_PEER_HAS_ENDPOINT,
        .PublicKey = ...,
        .Endpoint = ...,
        .AllowedIPsCount = 2
    },
    .FirstPeerAllowedIP1 = { ... },
    ...
};
WireGuardSetConfiguration(Adapter1, &Config.Interface, sizeof(Config));
WireGuardSetAdapterState(Adapter1, WIREGUARD_ADAPTER_STATE_UP);

You are highly encouraged to read the example.c short example to see how to put together a simple network tunnel. The example one connects to the demo server.

The various functions and definitions are documented in wireguard.h as well as in the reference below.

API Reference

Type: WIREGUARD_ADAPTER_HANDLE - opaque type to an instance of a WireGuard adapter.

Function: WireGuardCreateAdapter - creates a new adapter.

WIREGUARD_ADAPTER_HANDLE WireGuardCreateAdapter(LPCWSTR Name, LPCWSTR TunnelType, const GUID *RequestedGUID);

Typedef'd as WIREGUARD_CREATE_ADAPTER_FUNC. Returns a WIREGUARD_ADAPTER_HANDLE if successful, which must be released with WireGuardCloseAdapter; otherwise returns NULL and sets LastError.

Parameters

Type	Name	Description
LPCWSTR	Name	The requested name of the adapter. Zero-terminated string of up to MAX_ADAPTER_NAME-1 characters.
LPCWSTR	TunnelType	Name of the adapter tunnel type. Zero-terminated string of up to MAX_ADAPTER_NAME-1 characters.
GUID *	RequestedGUID	The GUID of the created network adapter, which then influences NLA generation deterministically. If it is set to NULL, the GUID is chosen by the system at random, and hence a new NLA entry is created for each new adapter.

Function: WireGuardOpenAdapter - opens an existing adapter.

WIREGUARD_ADAPTER_HANDLE WireGuardOpenAdapter(LPCWSTR Name);

Typedef'd as WIREGUARD_OPEN_ADAPTER_FUNC. Returns a WIREGUARD_ADAPTER_HANDLE if successful, which must be released with WireGuardCloseAdapter; otherwise returns NULL and sets LastError.

Parameters

Type	Name	Description
LPCWSTR	Name	The requested name of the adapter. Zero-terminated string of up to MAX_ADAPTER_NAME-1 characters.

Function: WireGuardCloseAdapter - closes an open adapter and releases its resources.

VOID WireGuardCloseAdapter(WIREGUARD_ADAPTER_HANDLE Adapter);

Typedef'd as WIREGUARD_CLOSE_ADAPTER_FUNC. Releases WireGuard adapter resources and, if adapter was created with WireGuardCreateAdapter, removes adapter.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.

Function: WireGuardGetAdapterLUID - gets the LUID of an adapter.

VOID WireGuardGetAdapterLUID(WIREGUARD_ADAPTER_HANDLE Adapter, NET_LUID *Luid);

Typedef'd as WIREGUARD_GET_ADAPTER_LUID_FUNC. Returns the LUID of the adapter into the variable passed as the Luid argument.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
NET_LUID * (out)	Luid	Pointer to receive adapter LUID.

Function: WireGuardGetRunningDriverVersion - gets the version of the loaded driver.

DWORD WireGuardGetRunningDriverVersion(VOID);

Typedef'd as WIREGUARD_GET_RUNNING_DRIVER_VERSION_FUNC. Returns the version of the WireGuardNT driver currently loaded, or zero on error and sets LastError, which is ERROR_FILE_NOT_FOUND if WireGuardNT is not currently loaded.

Function: WireGuardDeleteDriver - deletes driver if not in use.

BOOL WireGuardDeleteDriver(VOID);

Typedef'd as WIREGUARD_DELETE_DRIVER_FUNC. Deletes the WireGuardNT driver if there are no more adapters in use, and returns TRUE if successful, or returns FALSE if not and sets LastError.

Enumeration: WIREGUARD_LOGGER_LEVEL - determines level of logging.

Name	Description
WIREGUARD_LOG_INFO	Informational
WIREGUARD_LOG_WARN	Warning
WIREGUARD_LOG_ERR	Error

Callback type: WIREGUARD_LOGGER_CALLBACK - called for each log message.

VOID WireGuardLoggerCallback(WIREGUARD_LOGGER_LEVEL Level, DWORD64 Timestamp, LPCWSTR Message);

Typedef'd as WIREGUARD_LOGGER_CALLBACK. Called by the library on each log message.

Parameters

Type	Name	Description
WIREGUARD_LOGGER_LEVEL	Level	Message level.
DWORD64	Timestamp	Message timestamp in in 100ns intervals since 1601-01-01 UTC.
LPCWSTR	Message	Message text.

Function: WireGuardSetLogger - registers logger callback function.

VOID WireGuardSetLogger(WIREGUARD_LOGGER_CALLBACK NewLogger);

Typedef'd as WIREGUAR_SET_LOGGER_FUNC. After registration, the callback may be called concurrently by multiple threads. It is up to the supplied callback function, NewLogger, to handle synchronization. If NewLogger is NULL, logging is disabled.

Parameters

Type	Name	Description
WIREGUARD_LOGGER_CALLBACK	NewLogger	Pointer to callback function to use as a new global logger.

Enumeration: WIREGUARD_ADAPTER_LOG_STATE - determines adapter log generation.

Name	Description
WIREGUARD_ADAPTER_LOG_OFF	No logs are generated from the driver.
WIREGUARD_ADAPTER_LOG_ON	Logs are generated from the driver.
WIREGUARD_ADAPTER_LOG_ON_WITH_PREFIX	Logs are generated from the driver, adapter index-prefixed.

Function: WireGuardSetAdapterLogging - sets whether adapter logs are generated.

BOOL WireGuardSetAdapterLogging(WIREGUARD_ADAPTER_HANDLE Adapter, WIREGUARD_ADAPTER_LOG_STATE LogState);

Typedef'd as WIREGUARD_SET_ADAPTER_LOGGING. Sets whether and how the specified adapter logs to the logger previously set by WireGuardSetLogger. Returns TRUE if successful, or returns FALSE if not and sets LastError.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
WIREGUARD_ADAPTER_LOG_STATE	LogState	Adapter logging state.

Enumeration: WIREGUARD_ADAPTER_STATE - determines adapter state.

Name	Description
WIREGUARD_ADAPTER_STATE_DOWN	Down
WIREGUARD_ADAPTER_STATE_UP	Up

Function: WireGuardSetAdapterState - sets state of adapter.

BOOL WireGuardSetAdapterState(WIREGUARD_ADAPTER_HANDLE Adapter, WIREGUARD_ADAPTER_STATE State);

Typedef'd as WIREGUARD_SET_ADAPTER_STATE. Sets the specified adapter up or down. Note that sockets used by the specified adapter are owned by the process that sets the adapter up. Returns TRUE if successful, or returns FALSE if not and sets LastError.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
WIREGUARD_ADAPTER_STATE	State	Adapter state.

Function: WireGuardGetAdapterState - gets state of adapter.

BOOL WireGuardGetAdapterState(WIREGUARD_ADAPTER_HANDLE Adapter, WIREGUARD_ADAPTER_STATE *State);

Typedef'd as WIREGUARD_GET_ADAPTER_STATE. Gets whether the specified adapter is up or down. Returns TRUE if successful, or returns FALSE if not and sets LastError.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
WIREGUARD_ADAPTER_STATE (out)	State	Pointer to adapter state.

Structure: WIREGUARD_INTERFACE - an interface.

Type	Name	Description
WIREGUARD_INTERFACE_FLAG	Flags	Bitwise combination of flags.
WORD	ListenPort	Port for UDP listen socket, or 0 to choose randomly.
BYTE[WIREGUARD_KEY_LENGTH]	PrivateKey	Private key of interface.
BYTE[WIREGUARD_KEY_LENGTH]	PublicKey	Corresponding public key of private key (unused on set).
DWORD	PeersCount	Number of peer structures following this structure.

Structure: WIREGUARD_PEER - a peer.

Type	Name	Description
WIREGUARD_PEER_FLAG	Flags	Bitwise combination of flags.
DWORD	Reserved	Reserved; must be zero.
BYTE[WIREGUARD_KEY_LENGTH]	PublicKey	Public key, the peer's primary identifier.
BYTE[WIREGUARD_KEY_LENGTH]	PresharedKey	Preshared key for additional layer of post-quantum resistance.
WORD	PersistentKeepalive	Persistent keep-alive seconds interval, or 0 to disable.
SOCKADDR_INET	Endpoint	Endpoint, with IP address and UDP port number.
DWORD64	TxBytes	Number of bytes transmitted (unused on set).
DWORD64	RxBytes	Number of bytes received (unused on set).
DWORD64	LastHandshake	Time of the last handshake, in 100ns intervals since 1601-01-01 UTC (unused on set).
DWORD	AllowedIPsCount	Number of allowed IP structures following this structure.

Structure: WIREGUARD_ALLOWED_IP - an IP network range.

Type	Name	Description
Union	Address	IP address; the V4 member is a IN_ADDR and the V6 member is a IN6_ADDR.
ADDRESS_FAMILY	AddressFamily	Address family, either AF_INET or AF_INET6.
BYTE	Cidr	The CIDR of the address range.

Constant: WIREGUARD_KEY_LENGTH - the length of a key.

All WireGuard keys -- public, private, or pre-shared -- are 32 bytes in length.

Enumeration: WIREGUARD_INTERFACE_FLAG - bitwise flags for interfaces.

These values may be or'd together.

Name	Description
WIREGUARD_INTERFACE_HAS_PUBLIC_KEY	The PublicKey field is set (unused on set).
WIREGUARD_INTERFACE_HAS_PRIVATE_KEY	The PrivateKey field is set.
WIREGUARD_INTERFACE_HAS_LISTEN_PORT	The ListenPort field is set.
WIREGUARD_INTERFACE_REPLACE_PEERS	Remove all peers before adding new ones (unused on get).

Enumeration: WIREGUARD_PEER_FLAG - bitwise flags for peers.

These values may be or'd together.

Name	Description
WIREGUARD_PEER_HAS_PUBLIC_KEY	The PublicKey field is set.
WIREGUARD_PEER_HAS_PRESHARED_KEY	The PresharedKey field is set.
WIREGUARD_PEER_HAS_PERSISTENT_KEEPALIVE	The PersistentKeepAlive field is set.
WIREGUARD_PEER_HAS_ENDPOINT	The Endpoint field is set.
WIREGUARD_PEER_REPLACE_ALLOWED_IPS	Remove all allowed IPs before adding new ones (unused on get).
WIREGUARD_PEER_REMOVE	Remove specified peer (unused on get).
WIREGUARD_PEER_UPDATE_ONLY	Do not add a new peer (unused on get).

Function: WireGuardSetConfiguration - sets configuration of adapter.

BOOL WireGuardSetConfiguration(WIREGUARD_ADAPTER_HANDLE Adapter, const WIREGUARD_INTERFACE *Config, DWORD Bytes);

Typedef'd as WIREGUARD_SET_CONFIGURATION. Sets the configuration of the specified adapter. The Config argument represents a WIREGUARD_INTERFACE structure, immediately followed in memory by zero or more WIREGUARD_PEER or WIREGUARD_ALLOWED_IP structures. Returns TRUE if successful, or returns FALSE if not and sets LastError.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
WIREGUARD_INTERFACE *	Config	Adapter configuration.
DWORD	Bytes	Number of bytes of Config allocation.

Function: WireGuardGetConfiguration - gets configuration of adapter.

BOOL WireGuardGetConfiguration(WIREGUARD_ADAPTER_HANDLE Adapter, WIREGUARD_INTERFACE *Config, DWORD *Bytes);

Typedef'd as WIREGUARD_GET_CONFIGURATION. Gets the configuration of the specified adapter. The Config argument represents a WIREGUARD_INTERFACE structure, immediately followed in memory by zero or more WIREGUARD_PEER or WIREGUARD_ALLOWED_IP structures. Returns TRUE if successful, or returns FALSE if not and sets LastError. If LastError is ERROR_MORE_DATA, Bytes is updated with the number of bytes needed for successful operation. Since that byte value can change, this function should be called in a tight loop until success or until the error is not ERROR_MORE_DATA.

Parameters

Type	Name	Description
WIREGUARD_ADAPTER_HANDLE	Adapter	Adapter handle obtained with WireGuardCreateAdapter or WireGuardOpenAdapter.
WIREGUARD_INTERFACE * (out)	Config	Adapter configuration.
DWORD * (in/out)	Bytes	Pointer to number of bytes of Config allocation, on input, and is updated when the function returns to the amount of bytes required.

Building

Do not distribute drivers or files named "WireGuard" or "wireguard" or similar, as they will most certainly clash with official deployments. Instead distribute wireguard.dll as downloaded from the wireguard-nt download server.

General requirements:

• Visual Studio 2019 with Windows SDK
• Windows Driver Kit

wireguard-nt.sln may be opened in Visual Studio for development and building. Be sure to run bcdedit /set testsigning on and then reboot before to enable unsigned driver loading. The default run sequence (F5) in Visual Studio will build the example project and its dependencies.

License

The entire contents of this repository, including all documentation and example code, is "Copyright © 2018-2021 WireGuard LLC. All Rights Reserved." Source code is licensed under the GPLv2. Prebuilt binaries from the wireguard-nt download server are released under a more permissive license suitable for more forms of software contained inside of the .zip files distributed there.